Method of fabricating deep submicron MOSFET with narrow gate length using thermal oxidation of polysilicon

摘要

The present invention relates to forming a narrow gate MOSFET having a local ion implantation to reduce the junction capacitance. A polysilicon layer is formed over a semiconductor substrate. An opening is formed in the polysilicon layer by using patterning and etching. Subsequently, a thermal oxidation is performed to oxidize the polysilicon layer into a polysilicon-oxide layer that is expanded in volume relative to the polysilicon layer thereby narrowing said opening. Then an ion implantation is performed by using said polysilicon-oxide layer as a mask.